Wireless telephones have received wide acceptance for use in cellular systems, and wireless user premises equipment applications. There are in addition new cellular telephone systems under development as well as wireless personal communication systems (PCS) for both the licensed and unlicensed bands. One of these is the patented STel Orthogonal CDMA telephone system.
An additional requirement has been identified in the operation of wireless telephone systems as compared to corded telephone systems as follows. When a user makes an emergency 911 call on a standard corded telephone, the location of the user is quickly determined because the physical location of the telephone is known and unchanging. It has been noted that when a user makes an emergency 911 call on these new wireless systems it may be difficult to identify the exact location of the user thereby making it difficult to provide emergency service to the caller in a timely manner. The reason for this is that a user operating within a wireless telephone system is not bound to remain in one given physical location since the users can "roam" anywhere within the physical bounds of the total system. This is possible because as the user moves about physically, i.e., "roams", the handset of the user is "handed-off" from one base station to the other. Thus, when operating within a wireless system it is necessary 1) for the user to always have access to the telephone system within a reasonable period of time, 2) for the 911 system to identify the base station through which the call is being made, and 3) that a physical location determination of the user handset relative to the base station be easily and quickly computed. Based on the realization of these added requirements, the FCC has defined an "Enhanced 911" requirement which must provide these capabilities in all future wireless telephone systems. The orthogonal CDMA system disclosed in the above-identified application and U.S. Pat. No. 5,375,140 contains all the features necessary to provide all these requirements with a minimum of added complexity or cost to the system hardware.